Possible forcing of global temperature by the oceanic tides

Area of Science:

• Climate Science
• Oceanography
• Astronomy

Background:

• Global surface air temperature shows decadal periodicity (1855-1900, post-1945) and ~6-year cycles (1900-1945).
• Solar irradiance changes (sunspot cycle) explain earlier but not later temperature periodicities.

Purpose of the Study:

• To propose a single mechanism explaining both observed temperature periodicities.
• To investigate the role of extreme oceanic tides in driving sea surface temperature variations.

Main Methods:

• Analysis of global temperature observations (A.D. 1855-present).
• Modeling tidal forcing based on lunar nodal cycles (18.6 years) and Earth-Moon-Sun alignment.
• Proposing a physical mechanism of increased vertical mixing due to extreme tides.

Main Results:

• Extreme oceanic tides cause sea surface temperature changes with alternating ~9-year and ~6-year periods.
• These alternations align with periods of strong tidal forcing near perihelion (~90-year intervals).
• Observed temperature periodicities (9-year and 6-year) match model predictions centered on A.D. 1881, 1974, and 1923.

Conclusions:

• Extreme oceanic tides, through enhanced vertical mixing, provide a unified explanation for observed near-decadal temperature periodicities.
• This tidal forcing mechanism may also influence climate variability on longer timescales, including millennial and longer.
• The interplay of lunar cycles and Earth-Sun proximity is a key driver of climate fluctuations.